Not Applicable
Not Applicable
The present invention relates in general to standard attachment fittings for wire rope and chain (WRandC) and more particularly, such fittings that are enhanced with weigh sensing capability to also perform load weighing functions.
There are a number of devices (some patented) that provide weighing capability to WRandC load lifting/support or pulling assemblies such as those often found in overhead crane systems. However, with regard to certain aspects of safety complications, weighing device/assembly complexity and component cost, these prior art devices can be subject to specific problems.
A typical prior art weighing device such as that outlined in U.S. Pat""s to Khachaturian et al., U.S. Pat. No. 5,429,007 and Khachaturian et al. U.S. Pat. No. 5,589,646 for WRandC lifting/support or pulling applications is a component within the said assembly that is required to lift/support or pull in addition to weighing a load. In order to ensure safety, and functionality consistent with the original tensile and impact loading specifications of the associated WRandC fittings, prior art weighing devices must be tested to meet such load performance specifications.
Such prior art weighing devices are additional lifting component(s) within a lifting/support or pulling assembly that subsequently require additional attachment fitting(s) increasing assembly complexity, cost and the possibility of assembly failure.
Such prior art weighing devices typically require a xe2x80x9cthin sectionxe2x80x9d in the body of the load sensor to focus load weight in order to achieve load weight measurement accuracy. This thin section reduces structural integrity of the weighing device.
Standard attachment fittings for wire rope and chain (WRandC) enhanced with weigh sensing capability to also perform load weighing functions. A membrane thin strain gauge element is affixed to the body of a said fitting in any one of a number of possible positions. Accurate load weight measurements are achieved from the focused linear load strain that results in the fitting when a typical tensile or non-typical compressive load (in the case of an eye bolt) is applied. The load weight measurements are transmitted through wiring or a wireless remote system to a suitably positioned readout display.
It is an object of the present invention to enhance standard attachment fittings for WRandC used in lifting/support or pulling applications to perform load weighing functions without modification to their basic design configuration whilst maintaining their original application functionality.
A feature of the present invention is that it provides the said enhancement without introducing a separate weigh scale unit that is required to lift/support the load in addition to providing weighing functionality. Therefore additional testing of the strain gauge to ensure that it meets the established WRandC fitting tensile and shock load performance specifications is not required to ensure safety.
Another feature of the present invention is that it allows a reduction in the number of said WRandC load supporting fitting assembly components thus reducing potential risk of assembly failure, reducing assembly complexity and reducing assembly cost.
Another feature of the present invention is that the need for a xe2x80x9cthin sectionxe2x80x9d in the WRandC fitting body to focus load weight in order to achieve load weight measurement accuracy is not required. The unmodified existing shape of the WRandC fitting produces focused linear load strain at specific determinable points on the fitting body permitting accurate load weight measurement. The elimination of the need for a weaker thin section further enhances safety.
Another feature of the present invention is its ability to retain said fitting assembly overload readings for viewing on a readout display to warn the use of potential permanent fitting distortion and further enhance safety.
Another feature of the present invention is that, when shackle fittings are used, the weigh sensing strain gauge element position will not interfere with the attachment and removal of the shackle pin.
Another feature of the present invention is that because of the reduction of WRandC load supporting fitting assembly components, the assembly length can be reduced thereby increasing the available load clearance from the floor in applications such as those involving overhead crane use.